tl;dr - If you update RVM only to have your shell settings tampered,
try looking to see if RVM has created a .bash_login file that
didn’t exist before.

Despite me using Rbenv almost exclusively now, there are one or two
machines lying around which still use RVM. On one such machine, I did
a rvm get head --auto which fixed some problems I was
having. Shortly afterwards, I opened a new session to said machine,
only to be greeted with a blank prompt. Huh?

Turns out, the RVM update landed up generating a ~/.bash_login
file. The nasty thing here is that a login shell (i.e. when you ssh
in) will try load files in the following order:

~/.bash_profile

~/.bash_login

~/.profile

Fact 1: I don’t have a .bash_profile. Fact 2: .profile is the
thing that loads .bashrc. Now, because the .bash_login file was
created, it landed up killing the code path that ultimately loaded my
.bashrc. Oops.